Low relapse rate of urinary tract infections from extended-spectrum beta-lactamase-producing bacteria in young children

Background Extended-spectrum-beta-lactamase (ESBL)-producing bacteria are an increasingly important cause of urinary tract infections (UTIs) worldwide. We evaluated clinical characteristics and associated risk factors of UTIs in young children according to ESBL-producing status and relapse rates. Methods All urinary culture results in patients younger than 2 years old were assessed, and only children with febrile UTIs from gram-negative bacterial infections were reviewed. Results Of 845 episodes evaluated, 146 (17.3%) were caused by ESBL-positive bacteria. Significant differences were observed in previous UTIs, use of antibiotics or history of hospitalization within previous 3 months, and underlying urinary abnormalities between the ESBL UTI and non-ESBL UTI groups. After 2 weeks of treatment completion, UTI relapse occurred in 2.7% of children in the ESBL group and 1.1% of children in the non-ESBL group (P=0.13). In the ESBL UTI group, relapse rate was not significantly different between patients treated with susceptible antibiotics and those treated with non-susceptible but clinically effective antibiotics. Conclusions Previous history of UTI, antibiotic treatment, or hospitalization within previous 3 months and underlying disease are risk factors for ESBL UTI in children under 24 months of age. However, relapse rate was <3% regardless of in vitro susceptibility of the treating antibiotics, as long as the antibiotics were clinically effective. We cautiously propose that we may continue the use of initial empirical antibiotics when a definite clinical response is observed, although further study is necessary to confirm the findings of this study.